在iOS中使用AVAudioRecorder获取用户的HeartBeat

Question

我需要使用AVAudioRecorder让用户每分钟心跳一次，并在我的应用程序中使用它。

我尝试使用AVAudioSession设置我的麦克风增益来获得I/P，但它无法获得心跳，有什么方法可以使用我的应用程序获得心跳？到目前为止我已经尝试过的代码

 NSArray *dirPaths;
NSString *docsDir;

dirPaths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
//here i took cache directory as saved directory you can also take   NSDocumentDirectory
docsDir = [dirPaths objectAtIndex:0];

NSString *soundFilePath = [docsDir stringByAppendingPathComponent:@"sound.caf"];//at this path your recorded audio will be saved

NSURL *soundFileURL = [NSURL fileURLWithPath:soundFilePath];

NSDictionary *recordSettings = [NSDictionary dictionaryWithObjectsAndKeys:

                                                [NSNumber numberWithInt:AVAudioQualityMin],
                                                AVEncoderAudioQualityKey,

                                                [NSNumber numberWithInt:16], 
                                                AVEncoderBitRateKey,

                                                [NSNumber numberWithInt: 2], 
                                                AVNumberOfChannelsKey,

                                                [NSNumber numberWithFloat:44100.0], 
                                                AVSampleRateKey,
                                                nil];

NSError *error = nil;
audioRecorder = [[AVAudioRecorder alloc]initWithURL:soundFileURL settings:recordSettings error:&error];
 AVAudioSession *audioSession = [AVAudioSession sharedInstance];
 [audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];
 [audioSession setActive:YES error:nil];
 [audioSession setInputGain:1.0 error:nil];

if( !audioRecorder ) {

    UIAlertView *alert  =
    [[UIAlertView alloc] initWithTitle: @"Warning" message: [error localizedDescription] delegate: nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [alert show];
    return;

}

if ( error )
{
    NSLog( @"error: %@", [error localizedDescription] );
}
else {
    [audioRecorder prepareToRecord];
    [self recordAudio];//Mehod to Record Audio
}

}

-(void) recordAudio
{
 if (!audioRecorder.recording)
  {
   audioRecorder.delegate = self;
  [audioRecorder recordForDuration:10];//Here i took record duration as 10 secs 

 }
 }

Answer 1

您可能想尝试使用峰值计功率技巧和以下教程中的低通滤波器代码。我想你的手机会在头顶的updateMeter上嗡嗡作响，以跟上你的心跳。基本逻辑是打开记录器，更新仪表，获得最大功率，运行滤波器，比较阈值以查看何时发生“节拍”，然后参考系统时间或使用重复计时器来运行上述功能。按手机麦克风裸露的胸部可能是最好的(没有辅助硬件)，imho。祝好运!如果你能让它工作，请让我们知道。

http://mobileorchard.com/tutorial-detecting-when-a-user-blows-into-the-mic/